Listeria, a bacterium that may lead to a form of food poisoning, is unusual in that it can thrive in the cold temperatures of your refrigerator, the U.S. Department of Health and Human Services says.

The agency's foodsafety.gov website says these foods can harbor the germ and trigger listeriosis, an infection that can be dangerous to pregnant women and others with a weaker immune system.

Common sources of listeria include:

Prepared deli meats and hot dogs.Refrigerated meat spreads and pates.Unpasteurized milk and other dairy products.Brie, camembert, feta and other cheeses that may be made with unpasteurized milk.Smoked, refrigerated seafood.Raw vegetable sprouts.